6666445 has 4 divisors (see below), whose sum is σ = 7999740. Its totient is φ = 5333152.

The previous prime is 6666437. The next prime is 6666449. The reversal of 6666445 is 5446666.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5446666 = 2 ⋅2723333.

It can be written as a sum of positive squares in 2 ways, for example, as 3575881 + 3090564 = 1891^2 + 1758^2 .

It is a cyclic number.

It is not a de Polignac number, because 6666445 - 2³ = 6666437 is a prime.

6666445 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6666449) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 666640 + ... + 666649.

It is an arithmetic number, because the mean of its divisors is an integer number (1999935).

Almost surely, 2^6666445 is an apocalyptic number.

It is an amenable number.

6666445 is a deficient number, since it is larger than the sum of its proper divisors (1333295).

6666445 is a wasteful number, since it uses less digits than its factorization.

6666445 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1333294.

The product of its digits is 103680, while the sum is 37.

The square root of 6666445 is about 2581.9459715494. The cubic root of 6666445 is about 188.2051197899.

The spelling of 6666445 in words is "six million, six hundred sixty-six thousand, four hundred forty-five".